Islandine: Coulomb Blockade
Quantum Foundations arc, page 26 of 193. Back to The Pixelated Physics Universe
Who they are
Islandine has one line, and says it often: “One question at a time.”
Islandine is a character of the Quantum Foundations arc: drawn in pixels, ruled by one piece of real physics, and never allowed to break it.
The physics
Coulomb blockade: on a small island with charging energy e²/2C ≫ kBT, electrons tunnel one at a time.
$$ \begin{gathered} E_C = \frac{e^{2}}{2C} \gg k_B T \end{gathered} $$
| Symbol | Meaning | SI unit |
|---|---|---|
| $E_C$ | charging energy | J |
| $e$ | elementary charge | C |
| $C$ | island capacitance | F |
| $k_B$ | Boltzmann constant | J/K |
| $T$ | temperature | K |
Sources
Crossovers
Islandine meets Pelletine (Shot Noise). Islandine lets electrons through one at a time. Pelletine hears the result: current made of discrete charges is noisy, and the size of the shot noise reveals the charge of each carrier.
Islandine meets Tallywick (Thermionic Emission). Islandine's blockade only holds while the charging energy e²/2C is far above k_BT. Tallywick's thermionic electrons show what happens when heat wins: electrons escape over a barrier at a rate set by an exponential in temperature.
Islandine meets Shielda (Debye Shielding). Shielda hides charge in a plasma by crowding opposite charges round it. Islandine's island is too small to hide anything: adding a single electron changes its energy by e²/2C, enough to block the next one.
Wear the lore
Concept keywords: Coulomb Blockade, Islandine, Quantum Foundations, physics lore, Pixelated Physics